Process of maturing and bleaching flour



I No Drawing.

' the action of the I To all whom it'may concern M Men.

aonn c.v BAKER, or nrnenrrnnn rnnn, ,nnw annsnx, assrenon 'ro WALLACE & TIEBNAN 00. rim, or BELLEVILLJE, new Jersey, A conrona'rron or New YORK, r EROCESS 01F MATURING AND BLEACHING- FLOUR.

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Be it known that 1, JOHN C. BAKER, acitizen (if the United States of America, residing-at Ri'dgefield Park, Bergen County,- State of New Jersey, have invented certain 'new and useful Improvements in Processes of Maturing and Bleaching Flour, ofwhich the following is a full, clear,'and exact description. v i Y It is a fact well'known in the art that flour may be matured and bleached by, treating it with dry chlorine gas and this is'a process that has beenlargely practiced. Supposedly,

gas in this case is the removal of the color of the oil in the. flour and in bringing about an improved baking 'qu'ality due to changes 'simllar to those which take place during" the natural process of ageing. p The treatment of flour, however, with chlorine is open to certain well recognized v objections. Any excess of chlorine seriously impairs the baking qualities of the flour aside from any other deleterious effect that it may produce. The chlorine with its diluent air mustbe very .dry or the effect is equallyunsatisfactory particularly upon the. bakingquality of the treated fiour'. Whatever the proportion ofv chlorine used moreover, its'bleaching properties extend no further than to decolorize the oil, and the color of cellular material in the flour, particularly noticeable in low grade flour, is not affected, although the baking quality is impaired.

Presumably the injurious action of chlorine on flour is due to the fact that'some constituents of the latter are chlorinated by the gas. Whereas an oxidizing action only is reaction.

desirable in bleaching and maturing. A still further injurious action due to the chlorine is attributable to its reaction with water, forming hydrochloric acid according to the 01 H OsHOCl HCl. The hydrochloric acid interferes with the characteristic properties ofthe gluten and reduces its strength when-applied in excess.

1 Recognizing and seeking to avoid these objections to the use of chlorine, I have sought for and discovered a better bleaching and maturin agent in hypochlorous acid. This I have ound when used for the purpose is harmless'and eifective in whateverproportions it may be used. The flour treated with I Specification of Letters Patent. Pambgnteq] Jam, 311 1922 Application filed February 2', 1920. Serial to. 355,802.

it is bleached and matured more perfectly and effectively than can be done by the use of chlorine, and with little of the injurious efi'ects of the latter. The presence of nioisture is not objectionable, as with other bleaching agents, and an excess of the acid maybe used without noticeably injurious ef fects. In the case of first clear or other inferior flours T have found that the color is greatly improved over that which can be obtamed by the use of other bleachingagents, and that this is due to the complete decolorization of the oil without injuring the gluten and also to an actual bleaching of the colored cellular constituents therein. This latter result renders it possible to use lower grades of flour than heretofore for the making of white bread.

The hypochlorous acid I use in'carrying outthis process may be produced in any convenient and known way. For examp1e,carbonic acid gas diluted with air may be passed through a solution or suspension ofbleaching powder. A bleaching powder may be mixed with water and a weak acid such as boric acid, or the proper amountof strong acid to produce the same efiect and then passingair or other inert gas overor through the mixture.

Again chlorine in solution may be united with the proper amount of alkali to give a neutral solution and the hypochlorous acid w Tn'the practical carrying out of my invention any of theabove described methods may be employed, but I prefer, and particularly for. high grade flour, to pass a chlorinated solution of water through an excess of crushed lime-stone, as this affords a continuous and economical process if carried out by using a solution of approximately 0.3% to 0.5% chlorine and passing it up through a tower containing crushed lime-.

stone and then delivering it into a trough and forcing air through the'solution in fine bubbles which carry off with them the hypochlorous acid in gaseous form. I

The air with its charge of hypochlorous acid, however produced, is brought continuously into intimate contact with the vflour to be treated. To facilitate this the flour is stirred, beaten, blown or otherwise violently agitated in the presence of the diluted acid.

In order to explain more specifically. the method which I have above generally described I have appended hereto a drawing illustrating,. largely diagrammatically, an";

I combined with a regulated flow of water entering through a valve-controlled inlet 5 to a pipe line 6, where it is taken upby the'water to form a chlorine solution.

This solution is introduced into a tower or extended chamber or receptacle 7 containing crushed lime-stone, and byv the action of which the chlorine is converted into hypochlorous acid. The solution is taken.

oil by a p pe 8 and delivered to a trough 9, where it collects.

Thetrough '9 has a false and porous bottom 10 and an overflow and water seal 11 1 from which the excess solution passes off to any suitable channel or receptacle, A fan or blower 12 is connected to the compartment under the porous bottom 10 and maintains-a pressure of air therein which not only prevents the solution from leaking down through the false bottom but forces air up through the latter. This air in a mass of very fine bubbles passes up through the solution and carries oil the hypochlorous acid into a tube or conduit 13 connected to the lower end of an inclined tube 14.

The upper end of the tube 14 is provided with a hopper 15 into which flour to be treated may be delivered. Extending through tube 14 is a worm 16 rotated by a pulley 17, whereby the flour as it descends through the tube is violently agitated in the ascending column of diluted hypochlorous acid from the conduit 13. In this way the lead from the lower to the conduit 13 containing a regulating valve 19 by means'of which a variable proportion of pure air may be admitted to the hypochlorous acid mixture and in this way its concentration may be closely determined.

As my invention resides chiefly'in the treatment of flour by hypochlorous acid, it

may be carried out in other ways than by the introduction of this acidcinto the flour form an outside source. For example, I may pass .into the flour chlorine monoxide as this forms pure hypochlorous acid upon uniting with the water in the flour, according to the formula Cl O+H Os2HOCL This discovery is of great practical and commercial value, and results not only in an improved product but afi'ords a means of bleaching and maturing such substances as wheat flour in a more economical and practical way.

lVhat I claim as my invention is 1. The method of bleaching and maturing fiour, which consists in passing through the same. and in intimate contact with its particles hypochlorous acid in the form of a gas.

2. The method of bleaching and maturing flour which consists in exposing the same to intimate contact with hypochlorous acid diluted with an inert gas.

3. The method of bleaching and maturing flour, which consists in agitating a body of the same in the presence of hypochlorous acid and air.

4. The method of bleaching and maturing flour which consists in agitating a body of the same in an atmosphere of hypochlorous acid and an inert gas, whereby the particles of flour are brought into intimate contact with the hypochlorous acid.

In testimony whereof I hereunto afiix my signature.

7 JOHN C. BAKER 

